Conventionally, non-volatile memory (NVM) 100, such as flash memory, of a system is provided with four blocks (hereinafter referred to as first block 110, second block 120, third block 130 and fourth block 140, respectively), which are used respectively to store a default value 110a, a current configuration value 120a, a prior configuration value 130a, and a default-recovery value for 140a. 
Referring to FIG. 1A, during an initialization sequence, the default value 110a in the first block 110 of the non-volatile memory 100 is loaded into volatile memory 200, such as DDR (double data rate) memory by a memory control unit.
Referring to FIG. 1B, the configuration value executed during a previous shutdown and recorded in the third block 130 (hereinafter referred to as the prior configuration value 130a) is then loaded into the volatile memory 200, and the default value 110a is modified according to the prior configuration value 130a. Thereby, the system can rapidly access the volatile memory 200.
Referring to FIG. 1C, during an operation of the system, the currently executing configuration value (hereinafter referred to as the current configuration value 120a) is stored into the second block 120 of the non-volatile memory 100 by means of mapping the current configuration value 120a into the second block 120 of the non-volatile memory 100 to reserve the data being executed. Referring to FIG. 1D, the configuration value executed during shutdown is stored in the third block 130 of the non-volatile memory 100 as the prior configuration value 130a. Thus, in the next boot-up sequence, the same configuration values can be executed by loading the prior configuration value 130a. 
Referring to FIG. 1E, when a default-value recovery is executed, the system will read the default-recovery value 140a stored in the fourth block 140 of the non-volatile memory 100, and write it into the volatile memory 200.
The conventional system data management structure needs two spaces to store the default value for initialization and the default value for recovery. However, conservation of memory and storage space has become a very important issue.